Method and system for the continuous ranking of competitors during a race of a slalom skiing sports discipline

ABSTRACT

A method for the continuous ranking of a competitor during a race of a slalom skiing type sports discipline includes the following iterative steps: a step of measuring the variation in the lateral angle of the gliding board about a predefined axis, a step of detecting the moment when the angle passes through a predefined value, a step of recording the competitor&#39;s run time corresponding to the detected moment, a step of comparing the stored run time with those of the preceding competitors for the corresponding detected moment, and a step of ranking the competitor with respect to the preceding competitors as a function of the run time of each competitor. A ranking system implements the method.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to European Patent Application No.18190315.4 filed on Aug. 22, 2018, the entire disclosure of which ishereby incorporated herein by reference.

FIELD OF THE INVENTION

The invention concerns a method for the continuous ranking ofcompetitors during a race of a slalom skiing type sports discipline,wherein the competitor is provided with at least one gliding board, suchas skis or a snowboard.

The invention also concerns a continuous ranking system for implementingthe method.

BACKGROUND OF THE INVENTION

In a ski or board sports competition, such as a slalom or giant slalomski race, which may have one or more runs, the race is made moreappealing to spectators or television viewers by displaying theintermediates times of the competitor on the piste, in order to rank hisor her current position relative to the preceding competitors. Theintermediate times are, for example, measured by means of a light gatebetween two photoelectric cells, which are placed a few metres apartfrom each other, and which activate the instantaneous recording of thetimer value when the competitor crosses the gate. However, the terrainconfiguration and the risk of untimely activation by members of theorganisation restrict its use on the piste.

Another method consists in manually activating the recording of thetimer value as the competitor passes, but the accuracy and reliabilityare not high enough.

To determine the exact time of passage of competitors, there exists amethod and a system disclosed in Patent No. WO2016174612, in whichmagnets are placed along the course, preferably on each gate. Themagnets are detected by a magnetometer worn by the competitor, and thedata is transmitted so that the time of passage of the competitor ateach gate is known. However, implementation is long, since each magnethas to be placed in the snow, which is all the more inconvenient whenthe course is changed between two runs. Further, the range of themagnets is not always sufficient when a competitor passes at a greaterdistance from the gate.

In another Patent (WO2010119084), accelerometers are arranged in theslalom gates or poles, to detect passage of the competitor. However,such a device cannot identify the gates in order to differentiatebetween them, and also does not facilitate replacement of a gate duringa race.

It is also to be noted that it is possible to envisage continuouslymeasuring speed by using a receiver of a satellite tracking system ofthe GPS/GNSS type. Depending on interference due to multiple signalpaths, to the sky being blocked by mountains or other objects and togeometric dilution of accuracy, an accuracy of 95% can nonetheless beachieved. On a mountain slope with an inclination of 45°, horizontalspeed is 30% lower than three-dimensional speed. In order to workaccurately on a racing skier, the GPS receiver must be placed on theskier's helmet, but this represents an unacceptable safety risk during arace. Further, as the sensor is not attached to the ski, there is a lackof precision due to movements between the head and the ski. Although GPStechnology normally permits speed measurement in three directions, theuser of the GPS device only receives two-dimensional speed horizontally.This may result in a big difference for the skier compared to his actualspeed, which is a drawback.

SUMMARY OF THE INVENTION

It is thus an object of the invention to overcome the drawbacks of theaforementioned state of the art by proposing a method for the continuousranking of competitors during a race of a slalom skiing sportsdiscipline, the competitor being provided with at least one glidingboard, such as skis or a snowboard, wherein it is possible to rank thecompetitor with respect to the preceding competitors and regularlyupdate the ranking throughout the race.

To this end, the invention concerns a method for the continuous rankingof competitors during a race of a slalom skiing sports discipline,wherein the competitor is provided with at least one gliding board, suchas skis or a snowboard.

The method is remarkable in that it includes the following iterativesteps:

-   -   a step of measuring the variation in the lateral angle of the        gliding board about a predefined axis,    -   a step of detecting the moment when the angle passes through a        predefined value,    -   a step of recording the competitor's run time corresponding to        the detected moment,    -   a step of comparing the stored run time with those of the        preceding competitors for the corresponding detected moment, and    -   a step of ranking the competitor with respect to the preceding        competitors as a function of the run time of each competitor.

Thus, only one parameter is monitored—the lateral orientation of thegliding board, for example a ski or snowboard—to determine the momentswhen the competitor changes position between two slalom turns. Thechanges in lateral orientation generally occur between the obstaclesthat competitors have to zigzag around, for example gates or poles.

Whatever the trajectories of the competitor, the changes in orientationgenerally occur at the same level of the ski slope between the gates.Consequently, by detecting the moments at which they occur, it ispossible to follow the progress of the competitor throughout the slalomand to determine the run times of the competitors between each change inorientation. Thus, run times are recorded progressively throughout theslalom, each recorded time corresponding to a change in orientation ofthe skis.

The recorded run time is compared to the run times recorded for thepreceding competitors for a corresponding detected moment. Thus, thecompetitor performing the slalom can be ranked with respect to thepreceding competitors at that moment. The place that the competitoroccupies at that moment in the race is known.

At each new detected moment, the ranking of the competitor isre-evaluated by means of this method. The ranking of the competitor isthus updated very frequently, virtually between each obstacle of theslalom.

As a result of this method, it is sufficient to monitor a singleparameter—the angle of lateral rotation of the ski with respect to theplane of the slalom piste—to determine the run time to be recorded andto compare it to the preceding competitors. This is thus a reliablemethod that is technically simple to implement, which frequently updatesthe ranking of the competitor and follows the changes of thecompetitor's position in the ranking throughout the race.

Further, the method does not require any complex equipment on the courseor on the slalom obstacles. Further, no external factor is used andrelied upon, such as a satellite system, for example.

According to a particular embodiment of the invention, in the measuringstep, the predefined axis is chosen to be oriented substantially alongthe longitudinal axis of the gliding board, the lateral angle beingmeasured with respect to the plane of the slope of the course.

According to a particular embodiment of the invention, in the detectionstep, the value of the predefined angle is chosen to be zero, thegliding board being substantially parallel to the plane of the piste.

According to a particular embodiment of the invention, in the detectionstep, the sign of the angle value is detected.

According to a particular embodiment of the invention, in the detectionstep, moments are detected for two angle values, a first type of momentwhen the angle value changes from a value less than a value greater thanor equal to a first predefined value, and a second type of moment whenthe angle changes from a greater value to a value less than or equal toa second predefined value.

According to a particular embodiment of the invention, in the recordingstep, the first types of moment are associated with a turn in a firstdirection, substantially orthogonal to the predefined axis, and thesecond types of moment are associated with a turn in the oppositedirection to the first turn, for example right and left.

According to a particular embodiment of the invention, the firstpredefined value is comprised in a range of 3° to 30°, preferably of 5°to 15°, for example 10°, and the second predefined value is comprised ina range of −30° to −3°, preferably of −15° to −5°, for example −10°.

According to a particular embodiment of the invention, in the comparisonstep, a mean run time is computed over a series of consecutive detectedmoments, for example over the last four detected moments.

According to a particular embodiment of the invention, in the rankingstep, the competitor is ranked with respect to the preceding competitorsas a function of the mean run time.

According to a particular embodiment of the invention, the ranking stepis performed after a predefined number of detected moments, for exampleafter the fourth detected moment.

According to a particular embodiment of the invention, the methodincludes an additional step of transmitting the recorded time, betweenthe detection step and the recording step.

According to a particular embodiment of the invention, the methodincludes an additional step of displaying the competitor's ranking forthe detected moment.

According to a particular embodiment of the invention, in the displaystep, the competitor's run time for the detected moment is alsodisplayed.

The invention concerns a method for the continuous ranking ofcompetitors during a race of a slalom skiing type sports discipline, thecompetitor being provided with at least one gliding board, such as skisor a snowboard, for implementation of the continuous ranking methoddescribed above.

To this end, the system includes:

-   -   a measurement unit for measuring the variation in the lateral        angle of the gliding board about a predefined axis, for example        an inertial measurement unit provided with a gyroscope.    -   a detection unit configured to detect the moment when the angle        passes through a predefined value,    -   a device for measuring the run time of the competitors,    -   a processing unit configured to record the competitor's run time        when it receives a detection signal, to compare it with those of        the preceding competitors for the corresponding detected moment,        and to rank the competitor with respect to the preceding        competitors as a function of the run time of each competitor.

According to a particular embodiment of the invention, the systemincludes a portable transponder module provided with the measurementunit, the detection unit and a transmitter for transmitting thedetection signal to the processing unit.

According to a particular embodiment of the invention, the transpondermodule is arranged on the competitor's ski boot.

According to a particular embodiment of the invention, the systemincludes a ranking display unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, advantages and features of the ranking method and systemaccording to the invention will appear more clearly in the followingdescription of at least one non-limiting embodiment illustrated by thedrawings, in which:

FIG. 1 is a schematic representation of a slalom ski course for whichthe method according to the invention is used.

FIG. 2 is a synoptic diagram of a method for ranking a competitoraccording to the invention.

FIG. 3 is a graph representing the variations in the lateral angle ofthe gliding board during a slalom ski race.

FIG. 4 is a graph representing the counting of the number of left andright turns performed with the method.

FIG. 5 is a table showing an example of the ranking obtained with themethod of the invention.

FIG. 6 is a schematic representation of a ranking system according tothe invention.

DETAILED DESCRIPTION OF THE INVENTION

According to the invention, the method is arranged to allow thecontinuous ranking of a competitor with respect to the precedingcompetitors during a race of a slalom ski type sports discipline. Itconcerns, for example, descending a slalom or giant slalom piste withskis or a snowboard. The invention can also be applied to any boardsport which requires frequent turns to be made.

The term ‘continuous’ means that the ranking is regularly updated, andthat it is frequently repeated during the competitor's run. Thecompetitor is provided with at least one gliding board, such as skis ora snowboard, which allow him to glide over the piste, which is coveredwith snow.

During a slalom race 13, as represented in FIG. 1, the competitor has toclear obstacles by making turns around them from a predefined side. Thecourse 13 taken by the competitor is represented in dash lines inFIG. 1. The obstacles are, for example, slalom poles or gates 2 plantedin the snow. Generally, the successive turns are oriented in oppositedirections. For example, facing downhill on the piste, the competitormakes a left turn 3 to turn around a first gate 2 which he has to passon the right side of the piste, and then a right turn 4 to turn around asecond gate 2 which he has to pass on the left side. Thus, between twogates, the competitor has to suddenly change position to make a turn inthe opposite direction. To achieve this, he has to change the lateralorientation of the skis on the piste to turn in the other direction.These changes are represented by small circles in FIG. 1.

Detecting the moment at which the competitor has changed the lateralposition of the skis determines the points of passage 5 on course 13 forwhich run times are measured, which the competitor's ranking to beupdated with respect to the preceding competitors, at each point ofpassage 5 on course 13.

To this end, method 1, represented in FIG. 2, consists in a first step6, of measuring the variation in the lateral angle of the gliding boardabout a predefined axis. Preferably, a predefined axis orientedsubstantially along the longitudinal axis of the gliding board ischosen. When the board is flat on the piste the angle is zero, and whenthe board is raised on one side or the other, it forms a positive angleon one side and a negative angle on the other with the piste position.Thus, the angle that the gliding board forms with the piste is measuredon the predefined axis.

In a second step 7, the moment at which the angle passes through apredefined value is measured.

According to a first embodiment of method 1, a zero angle value ischosen so that the gliding board is substantially parallel to the planeof the piste when this moment is detected. Thus, when the competitorchanges the lateral orientation of his skis between two turns, henecessarily passes through a zero lateral angle value.

According to a second embodiment of method 1, the sign of the anglevalue is also detected to determine whether the angle has passed througha zero value. Moreover, it is possible to deduce the type of turn fromthe sign. For example, when the angle becomes negative, a left turn isdetected, and when the angle becomes positive, a right turn is detected.Each detection can thus be associated with the orientation of the turn,be it left or right. By associating the type of turn with eachdetection, it is possible to track whether the competitor is followingthe same course as the other competitors.

According to a third embodiment of method 1, moments are detected fortwo angle values, a first type of moment when the angle value changesfrom a value less than a value greater than or equal to a firstpredefined value, and a second type of moment when the angle changesfrom a greater value to a value less than or equal to a secondpredefined value.

The first types of moment are associated with a turn in a firstdirection, substantially orthogonal to the predefined axis, and thesecond types of moment are associated with a turn in the oppositedirection to the first turn. For example, a right turn is detected whenthe angle has a value greater than or equal to the first predefinedvalue and a left turn when the angle has a value less than or equal to asecond predefined value.

The first predefined value is comprised in a range of 3° to 30°,preferably of 5° to 15°, and the second predefined value is comprised ina range of −30° to −3°, preferably of −15° to −5°, to count all theturns. For example, an angle of 10° is chosen for the first value and−10° for the second value. In this example, a left turn is detected whenthe angle reaches −10°, even though it was greater than this value, anda right turn when the angle reaches 10° even though the angle was lessthan this angle.

In this third embodiment, there is a hysteresis effect in detection, toavoid detecting small turns that the competitor makes, for example, toright himself, and which is not due to avoiding a gate. In the lastexample, turns are not detected for values less than 10° and more than−10°.

In the example of FIG. 2, method 1 includes a third additional step 8 oftransmitting the moment when the angle passes through a predefinedvalue, between the detection step and the recording step. This step isoptional and exists, for example, to provide the connection between amobile detector such as a transponder, and a processing unit whichperforms the rest of method 1. For a mobile system which performs theentire method 1, there is no transmission step.

Method 1 include a fourth step 9 of recording the competitor's run timecorresponding to the detected moment. The competitor's run time is timedfrom the start by the usual timing means. Thus, as soon as a moment isdetected, the current run time is instantaneously recorded to beassociated with the detected moment.

In the first embodiment, a run time is associated with each passage ofthe angle through the zero value.

In the second embodiment, a run time is associated with each change ofsign of the angle value. Further, the direction of the turn—right orleft—is known. It is thus possible to check whether the competitors havemade the same number of left and right turns.

In the third embodiment, a run time is associated as soon as the angleis greater than or equal to the first predefined value, or as soon asthe angle is less than or equal to the second predefined value. Further,the direction of the turn—left or right—is known, as in the secondembodiment.

The next step is a step 10 of comparing the stored run time with thoseof the preceding competitors for the corresponding detected moment.Advantageously, the stored run times of the competitor are tallied andthe last run time stored is compared with the stored run times of thepreceding competitors of the same order.

According to a particular embodiment, during the comparison step, a meanrun time is computed over a series of consecutive detected moments. Toincrease the ranking reliability, the mean value is, for example,computed over the last four detected moments. This thus avoid anerroneous ranking due to an anomaly in the course of the competitor

Using the recorded run time, there is then a step 11 of ranking thecompetitor with respect to the preceding competitors as a function ofthe run time of each competitor. In the embodiment wherein a mean runtime is computed over several moments, the competitor is ranked withrespect to the preceding competitors as a function of the mean run time.

Advantageously, the ranking step is performed after a predefined numberof detected moments, for example after the fourth detected moment. Thistherefore avoids creating a ranking over the first detected momentssince there is a risk of error.

In FIG. 2, method 1 includes an optional additional step 12 ofdisplaying the competitor's ranking for the detected moment. The rankingcan thus be followed by spectators or television viewers who arewatching the race. It is also possible to display the competitor's runtime to monitor how far ahead or behind the competitor is compared tothe preceding competitors.

The continuous ranking method 1 described above is implemented in aniterative manner throughout the competitor's run. Method 1 is repeatedin the order of steps described above to update the ranking frequently,here at each turn change of the competitor.

In graph 14 of FIG. 3, function 15 represents the value of the angle oflateral rotation of the sliding board about the predefined axis on aslalom ski sports course. The value of angle 16 is on the ordinate,while the abscissa represents time 17. As soon as the angle passesthrough the zero value of angle 18, the competitor has turned in adifferent direction. Each peak 19 of the function corresponds to a gatethat the competitor has turned around. Thus, by detecting the momentswhen the angle passes through the zero value, a run time between twogates is deduced.

FIG. 4 shows the way in which the left or right turns are counted as afunction of the sign of the angle seen in the graph of FIG. 3. Here, thesign of the angle is detected to deduce therefrom the nature of theturns. Function 21 has a rectangular profile, with positive rectangles21 or negative rectangles 2 according to the sign of the angle, eachrectangle representing a left or right turn. The positive valuerectangles correspond, for example, to the right turns, and the negativevalue rectangles to the left turns. The competitor has thus made thirtyright turns here and twenty-nine left turns, i.e. a final total offifty-nine turns. The fifty-nine turns are counted above the rectangularcurve, whereas the left and right turns are differentiated and inscribeddirectly on each corresponding rectangle.

An example ranking between several competitors, three in the example, isshown in Table 25 of FIG. 5, in which five moments G0, G1, G2, G3 and G4have been detected and ranked corresponding to five turns made during aslalom race. Five times of passage T01, T02, T03, T11, T12, T1, T21,T22, T23, T31, T32, T33, T41, T42, T43, were thus recorded for eachcompetitor at moments G0, G1, G2, G3 and G4. For the three times ofpassage G0, G1, G2, no ranking is performed, but a ranking 26, 27 isperformed for the fourth and fifth run times at moments G4 and G5.Further, the Table corresponds to the embodiment wherein a mean run timeis computed from the fourth detected moment, here for moments G3 and G4.The mean [Tij] is computed for a moment Gi, and for a competitor j, bythe following equation:

$\lbrack{Tij}\rbrack = \frac{{Tij} + {{T\left( {i - 1} \right)}j} + {{T\left( {i - 2} \right)}j} + {{T\left( {i - 3} \right)}j}}{4}$

Thus, from the computed means [T31], [T32], [T33], [T41], [T42], [T43],the competitors are ranked from the lowest mean to the highest mean formoments G3 and G4. For moment G3, the third competitor is the fastest,ahead of the first and second, while at detected moment G4, the secondcompetitor is faster than the first, with the third still the slowest.

The invention also relates to a system 30 for the continuous ranking ofa competitor during a race of a slalom skiing sports discipline. System30 is, in particular, suitable for implementing the method describedabove. FIG. 6 schematically represents the main elements, which composeranking system 30 in a slalom type race, such as a ski or snowboardrace. System 30 is arranged to rank the competitors in real time, i.e.live or continuously, while allowing live display of this ranking on ascreen or by television broadcast on a television to spectators ortelevision viewers.

System 30 includes one or more transponder modules 31, which are eachintended to be worn by a competitor, who wears it to measure, inparticular, the variation in lateral angle of the gliding board. Eachtransponder module 31 for the competition is disposed, for example, onone of the competitor's boots. Transponder module 31 includes atransmitter 32 provided with an antenna for transmitting a data signal,in particular a detection signal of a moment when the angle passesthrough the predefined value. For data signal transmission, the signalcarrier frequency may be comprised between 300 MHz and 3,000 MHz, andespecially, for example, at 433 MHz, 868 MHz or 915 MHz. Data modulationis achieved by amplitude modulation or frequency or phase modulation. Itmay be chosen from several carrier frequencies for transmission of thedata signal. Thus, various transmission channels may be selected.

Each transponder module includes a measurement unit 33 for measuring thevariation in the lateral angle of the gliding board about the predefinedaxis. Measurement unit 33 is, for example, an inertial measurement unit,which is a motion sensor generally formed of a 3-axis accelerometer, a3-axis gyroscope and a 3-axis magnetometer. The gyroscope measures theangle variation about the predefined axis. It is to be noted that asensor provided simply with a gyroscope is sufficient to measure theangular variation according to the method.

Transponder module 31 also includes a detection unit 34 configured todetect the moment when the measured angle passes through the predefinedvalue or values, and the sign of the angle if necessary. Consequently,as soon as the angle value is detected, the module instantaneouslytransmits a detection signal.

System 30 also includes one or more base stations 35, 36, 37 which caneach receive a signal transmitted by the antenna of transmitter 32 ofthe transponder module 31 in the race, particularly a detection signalof the moment when the competitor passes through the predefined value orvalues. Each base station 35, 36, 37 can receive the signal fromtransponder module 31, separately or together via a receiving antenna41, 42, 43. It is to be noted that each base station 35, 36, 37 of thedevice can be placed at a specific location on the racing track. Forexample, in a ski or snowboard race, base stations 35, 36, 37 could beplaced spaced apart from each other by 200 to 400 m between the startand finish of the course. Each base station 35, 36, 37 or at least onebase station can receive a data signal from the transponder module 31worn by the competitor during his run.

System 30 is also equipped with a timing device 38 and a display unit39. Timing device 38 controls the timing of each competitor's run, andthus measures the run time of the competitors from the start until thecompetitor finishes. Display unit 39 displays the ranking in real timeor continuously on at least one screen for spectators or televisionviewers via television broadcast devices or on the Internet.

System 30 further includes a processing unit 40 connected to the variousbase stations 35, 36, 37 and to timing device 38. The various basestations 35, 36, 37 can be connected by cable or also by wirelesscommunication in order to transmit the signal to processing unit 40 bycable or also by wireless transmission. Processing unit 40 is configuredto record the competitor's run time when it receives a detection signalfrom transmitter 32 of transponder module 31, transmitted by bases 35,36, 37. Processing unit 40 stores the run time for the detected momentand compares the run time with those of the preceding competitors forthe corresponding detected moment. Processing unit 40 then performs aranking of the competitor with respect to the preceding competitors as afunction of the run time of each competitor, according to any of theembodiments of the method described above. The ranking is simultaneouslytransmitted to display unit 39 for the spectators or television viewers.

The invention claimed is:
 1. A method for continuous ranking ofcompetitors during a race of a slalom skiing sports discipline along aracing track, a competitor being provided with at least one glidingboard, the method comprises the following iterative steps: measuring, bya sensor that includes a gyroscope and is arranged on a ski boot of thecompetitor, a variation in a lateral angle of the gliding board about apredefined axis; detecting, by a detector, a moment when the lateralangle passes through a predefined value; recording, by processingcircuitry communicatively coupled to a plurality of base stationslocated along the racing track, a run time of the competitorcorresponding to the detected moment; comparing, by the processingcircuitry that is communicatively coupled to the plurality of basestations located along the racing track, the recorded run time with runtimes of preceding competitors for the corresponding detected moment;and ranking, by the processing circuitry that is communicatively coupledto the plurality of base stations located along the racing track, thecompetitor with respect to the preceding competitors as a function ofthe run time of each competitor.
 2. The method according to claim 1,wherein, in the measuring, the predefined axis is chosen to be orientedalong a longitudinal axis of the gliding board, the lateral angle beingmeasured with respect to a plane of a piste of a slalom course.
 3. Themethod according to claim 2, wherein, in the detecting, the value of thepredefined angle is chosen to be zero, the gliding board being parallelto the plane of the piste.
 4. The method according to claim 3, wherein,in the detecting, a sign of the value of the angle is detected.
 5. Themethod according to claim 1, wherein, in the detecting, moments aredetected for two angle values, a first type of moment when the anglevalue changes from a value less than to a value greater than or equal toa first predefined value, and a second type of moment when the anglechanges from a greater value to a value less than or equal to a secondpredefined value.
 6. The method according to claim 5, wherein, in therecording, the first types of moment are associated with a turn in afirst direction, orthogonal to the predefined axis, and the second typesof moment are associated with a turn in an opposite direction to thefirst turn.
 7. The method according to claim 5, wherein the firstpredefined value is comprised in a range of 3° to 30°, and the secondpredefined value is comprised in a range of −30° to −3°.
 8. The methodaccording to claim 5, wherein the first predefined value is comprised ina range of 5° to 15°, and the second predefined value is comprised in arange of −15° to −5°.
 9. The method according to claim 1, wherein, inthe comparing, a mean run time is computed over a series of consecutivedetected moments over last four detected moments.
 10. The methodaccording to claim 9, wherein, in the ranking, the competitor is rankedwith respect to the preceding competitors as a function of the mean runtime.
 11. The method according to claim 1, wherein, the ranking isperformed after a predefined number of detected moments after a fourthdetected moment.
 12. The method according to claim 1, further comprisingtransmitting the recorded run time, between the detecting and therecording.
 13. The method according to claim 1, further comprisingdisplaying the ranking of the competitor for the detected moment. 14.The method according to claim 13, wherein, in the displaying, the runtime of the competitor for the detected moment is also displayed.
 15. Asystem for continuous ranking of competitors during a race of a slalomskiing sports discipline along a racing track, a competitor beingprovided with at least one gliding board, the system comprising: asensor that includes a gyroscope and is arranged on a ski boot of thecompetitor, configured to measure a variation in a lateral angle of thegliding board about a predefined axis; a detector configured to detect amoment when the lateral angle passes through a predefined value; a timerconfigured to time a run time of the competitor; and processingcircuitry communicatively coupled to a plurality of base stationslocated along the racing track, the processing circuitry configured torecord the run time of the competitor when the processing circuitryreceives a detection signal, to compare the run time with run times ofpreceding competitors for the corresponding detected moment, and to rankthe competitor with respect to the preceding competitors as a functionof the run time of each competitor.
 16. The system according to claim15, wherein the sensor, the detector, and a transmitter configured totransmit the detection signal to the processing circuitry are includedin a portable transponder.
 17. The system according to claim 16, whereinthe portable transponder, which includes the sensor, the detector, andthe transmitter, is configured to be arranged on the ski boot of thecompetitor, and the processing circuitry is configured to transmit thedetection signal to each of the plurality of base stations.
 18. Thesystem according to claim 15, further comprising a display to displaythe ranking.
 19. A method for continuous ranking of competitors during arace of a slalom skiing sports discipline along a racing track, acompetitor being provided with at least one gliding board, the methodcomprising: receiving, by processing circuitry communicatively coupledto a plurality of base stations located along the racing track, ameasurement of a variation in a lateral angle of the gliding board abouta predefined axis, the measurement being measured by a sensor thatincludes a gyroscope and is arranged on a ski boot of the competitor;receiving, by the processing circuitry that is communicatively coupledto the plurality of base stations located along the racing track, adetection of a moment when the lateral angle passes through a predefinedvalue; recording, by the processing circuitry that is communicativelycoupled to the plurality of base stations located along the racingtrack, a run time of the competitor corresponding to the detectedmoment; comparing, by the processing circuitry that is communicativelycoupled to the plurality of base stations located along the racingtrack, the recorded run time with run times of preceding competitors forthe corresponding detected moment; and ranking, by the processingcircuitry that is communicatively coupled to the plurality of basestations located along the racing track, the competitor with respect tothe preceding competitors as a function of the run time of eachcompetitor.
 20. The system according to claim 15, further comprising:the plurality of base stations, which are spaced apart from each otherby 200 to 400 m between a start and a finish of the racing track.